1. Field of the Invention
The present invention generally relates to an antenna apparatus, and especially relates to an antenna apparatus including
an element pattern,
a strip line for feeding electric power to the element pattern, and
a grounding pattern that counters the strip line, the strip line and the grounding pattern being formed by a pattern on a printed wiring board.
2. Description of the Related Art
In recent years and continuing, a radio-communications technology using UWB (ultra-wide band) attracts attention, since communications of radar positioning and a large transmission capacity are possible. The UWB, ranging between 3.1 and 10.6 GHz, has been approved by the US FCC (Federal Communication Commission) since 2002.
Communications using UWB employ a communication system wherein a pulse signal is transmitted in the super-wide band. For this reason, antennas used in the UWB have to be capable of transmitting and receiving with the super-wide band.
As an antenna at least for the 3.1-10.6 GHz frequency band approved by the FCC, an antenna consisting of a grounding plate and a feeder is proposed (Non-Patent Reference 1).
FIG. 1 is a block diagram of an example of a conventional UWB radio system 1.
The conventional radio system 1 consists of an antenna apparatus 11, a filter 12, and a transceiver circuit 13.
FIG. 2A and FIG. 2B are plan views of the conventional antenna apparatus 11. FIG. 2A shows an upper surface view, and FIG. 2B shows a bottom plan view.
The antenna apparatus 11 for transmitting and receiving in the UWB (ultra-wide-band) includes a printed wiring board 21, an element pattern 22, and a micro-strip line 23 for feeding electric power to the element pattern 22 that are formed on the upper surface of the printed wiring board 21. Further, the antenna apparatus 11 includes a grounding pattern 24 formed on the rear side of the printed wiring board 21, countering the micro-strip line 23.
The antenna apparatus 11 obtains a desired property by adjusting an angle θ between the grounding pattern 24 and a side of the element pattern 22, the side countering the grounding pattern 24.
[Non-Patent Reference 1]
“An omnidirectional and low-VSWR antenna for the FCC-approved UWB frequency band” by T. Taniguchi and T. Kobayashi (Tokyo Denki University) in 2003 IEEE AP-S International Symp., volume: 3, pp. 460-463, Jun. 22-27, 2003. (Disclosure on March 22 at B201 classroom).
[Description of the Invention]
[Problem(s) to be Solved by the Invention]
Nevertheless, it is desired that an antenna apparatus of this kind be installed in a personal computer., a portable communication apparatus, etc.; i.e., further miniaturization and thinner shape are desired.